I firt start off with a little free and a little paid advertising. The free part usually is the signature at many forums.
They really do help. I am looking to advertise my forum (MyIndya.Com) to another site serving the same purpose or close enough or who is getting the traffic that I am looking for. So I am ready to pay $$ for that. However, I wouldn't go with adwords and spend my money when most people click to help the website.